System and process for reacting a petroleum fraction

ABSTRACT

In one exemplary embodiment, a system for reacting a first feed can include a petroleum fraction having at least about 90%, by volume, with a boiling point of at least about 300° C. The system can include a bubble column reactor. The bubble column reactor, in turn, can include a first inlet for the first feed and a second inlet for a second feed including a gas rich in hydrogen. In addition, the petroleum fraction may be in counter-current flow with respect to the gas rich in hydrogen inside the bubble column reactor.

FIELD OF THE INVENTION

This invention generally relates to a system and a process for reactinga petroleum fraction.

DESCRIPTION OF THE RELATED ART

Typically, a hydrocracking process is used in a large number ofpetroleum refineries. Such a process can be used to react a feed, suchas a heavy crude oil residual fraction. In general, the hydrocrackingprocess can split feed molecules into smaller molecules having a higheraverage volatility and a greater economic value. At the same time, ahydrocracking process can improve material quality by increasing thehydrogen to carbon ratio of the stream and by removing sulfur andnitrogen.

In some hydrocarbon conversion processes, a slurry reactor or a bubblecolumn reactor (hereinafter may be referred to as a bubble columnreactor) receives feeds of a heavy crude oil residual fraction and a gasreactant, such as hydrogen. Generally, the heavy crude oil residualfraction is in co-current flow with the gas reactant inside the reactor.Unfortunately, these co-current processes can suffer from severaldisadvantages.

First, the upflow bubble column reactor typically has a low hydrogenpurity at the top of the reactor near the liquid product outlet.Regrettably, a high hydrogen purity at the outlet is generally desiredfor converting substances, such as pitch, one or more aromatics, sulfur,and nitrogen, in the heavy crude oil residual fraction. In addition, aco-current upflow design can be susceptible to solids accumulation atthe bottom of the reactor. These solids can be removed by activating anintermittent stream at the bottom of the reactor. But such a process mayrequire identification of such accumulated material, which can requiregreater vigilance of operating personnel or automated control systems toactivate the stream for removing the solids. In either case, additionalresources are required to remove the solids.

Consequently, it would be beneficial to provide a system that overcomesthese shortcomings.

SUMMARY OF THE INVENTION

In one exemplary embodiment, a system for reacting a first feed caninclude a petroleum fraction having at least about 90%, by volume, witha boiling point of at least about 300° C. The system can include abubble column reactor. The bubble column reactor, in turn, can include afirst inlet for the first feed and a second inlet for a second feedincluding a gas rich in hydrogen. In addition, the petroleum fractionmay be in counter-current flow with respect to the gas rich in hydrogeninside the bubble column reactor.

Another exemplary embodiment can provide a system for reacting a firstfeed in a plurality of bubble column reactors. The system can include afirst bubble column reactor and a second bubble column reactor. Thefirst bubble column reactor may receive first and second feeds. Thefirst feed can include a petroleum fraction having at least about 90%,by volume, with a boiling point of at least about 300° C., and thesecond feed may include a first gas rich in hydrogen. The petroleumfraction can be in counter-current flow with respect to the first gasrich in hydrogen in the first bubble column reactor. The second bubblecolumn reactor may receive a third feed of a bottom product from thefirst bubble column reactor including another petroleum fraction, and afourth feed of a second gas rich in hydrogen. The another petroleumfraction may be in counter-current flow with respect to the second gasrich in hydrogen in the second bubble column reactor.

A further exemplary embodiment can be a process for reacting a firstfeed including a petroleum fraction stream having at least about 90%, byvolume, with a boiling point of at least about 300° C. The process mayinclude passing counter-currently a petroleum fraction entraining acatalyst with respect to a gas rich in a hydrogen gas in a bubble columnreactor.

The embodiments disclosed herein can provide several benefits.Particularly, the petroleum fraction in counter-current reaction flowwith the gas can provide the highest hydrogen purity at an outlet tofacilitate converting pitch, one or more unsaturated compounds, one ormore aromatics, sulfur, and/or nitrogen. Desirably, the gas is in upflowand the petroleum fraction is in downflow. Moreover, hydrogen purity islowest near the petroleum fraction inlet, where conversion of pitch,unsaturated compounds, aromatics, sulfur, and/or nitrogen iscomparatively easier, and is highest near the petroleum fraction outlet.In addition, the counter-current arrangement can prevent theaccumulation of solids in the reactor because there is a continuousoutlet for the petroleum fraction from the bottom. What is more, thereactor can provide a gas-suspension separation at the top of thereactor. As a result, additional equipment, such as a hot separator, canbe eliminated. This can be particularly useful for a plurality ofreactors because the petroleum fraction product from the first reactorcan be fed directly to the next reactor without requiring additionalheating.

DEFINITIONS

As used herein, the term “fluid” can mean one or more gases and/or oneor more liquids.

As used herein, the term “gas” can mean a single gas or a solution of aplurality of gases. In addition, the term “gas” may include a solutionor a suspension, e.g., a vapor or an aerosol, of one or more liquidparticles and/or one or more solid particles, of the same or differentsubstances, in one or more gases.

As used herein, the term “liquid” can mean a single liquid, or asolution or a suspension of a plurality of liquids and/or solidparticles. A liquid can include a liquid entraining a plurality of solidparticles, such as a suspension of catalyst particles in a petroleumfraction, such as an atmospheric or a vacuum tower bottom. A suspensioncan include an unconverted, converted, or partially converted petroleumfraction.

As used herein, the term “petroleum fraction” generally means a heavyhydrocarbon fraction originating from sources such as a vacuum residue,an atmospheric residue, a vacuum gas oil, an atmospheric gas oil, aheavy atmospheric gas oil, a steam crack gas oil, deasphaltic gas oil,and/or a heavy catalytic cycle oil, although lighter fractions may alsobe present. The term “petroleum fraction” can refer to the fractionalone or the fraction suspending one or more solid particles, e.g.,catalyst particles. The term “petroleum fraction” can also refer to aheavy hydrocarbon fraction that has undergone conversion with a gasreactant inside a bubble column reactor to become, e.g., a product, andmay have a different composition and/or boiling point as compared to afeed petroleum fraction.

As used herein, the term “rich” can mean an amount generally of at leastabout 50%, and preferably about 70%, by mole, of a compound or class ofcompounds in a stream.

As used herein, the term “substantially” can mean an amount generally ofat least about 90%, preferably about 95%, and optimally about 99%, bymole, of a compound or class of compounds in a stream.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational, partial cross-sectional schematic depiction ofan exemplary bubble column reactor.

FIG. 2 is an elevational, partial cross-sectional schematic depiction ofa plurality of exemplary bottom column reactors.

DETAILED DESCRIPTION

Referring to FIG. 1, an exemplary system 100 for hydrogenating one ormore unsaturated aromatic and non-aromatic compounds, converting atleast one hydrocarbon compound comprised in, e.g., pitch, and/orremoving at least one of nitrogen and sulfur from one or morehetero-compounds in a petroleum fraction is depicted. The system 100 caninclude a bubble column reactor 200 that can receive a first feed 110and a second feed 130. The first feed 110 can include a petroleumfraction stream 102 combined with one or more catalyst particles in acatalyst stream 104. A combination of the petroleum fraction stream 102and the catalyst stream 104 can form a solid-in-liquid suspension as thefirst feed 110. Typically, at least about 90%, by volume, of thepetroleum fraction stream 102 has a boiling point of at least about 300°C., desirably over about 520° C., and optimally over about 524° C., asdetermined by ASTM D-1160-06. The petroleum fraction stream 102 caninclude a vacuum residue, an atmospheric residue, a vacuum gas oil, anatmospheric gas oil, a heavy atmospheric gas oil, a steam crack gas oil,a deasphaltic gas oil, and/or a heavy catalytic cycle oil, althoughlighter fractions may also be present. Desirably, the petroleum fractionstream 102 is at least one of an atmospheric tower bottom and a vacuumtower bottom, and can generally be referred to as a heavy hydrocarbonoil feed.

Regarding the catalyst stream 104, any suitable bubble column catalystcan be utilized. Exemplary catalyst particles can include at least onegroup VIII metal, preferably iron. One exemplary catalyst can be an ironsalt, such as iron sulfate, as disclosed in U.S. Pat. No. 4,963,247.Generally, the catalyst particles can be any suitable size. Someexemplary catalyst particles have, respectively, at least one dimensionless than about 45 microns, desirably less than about 10 microns, andoptimally less than about 5 microns. Preferably, the catalyst particlesare generally spherical in shape and have a diameter less than about 45microns, desirably less than about 10 microns, and optimally less thanabout 5 microns. The catalyst particles can comprise about 0.01—about4.0%, preferably about 0.5—about 3.0%, and optimally about 1.0—about2.5%, by weight, of the first feed 110 based on the weight of the firstfeed 110.

The second feed 130 can include a reactant gas, such as a gas rich inhydrogen, or a gas substantially including hydrogen. The gas can beprovided in amounts of about 150-about 9,000 standard m³/per m³,preferably about 200-about 2,000 standard m³/per m³, and optimally about500-about 1,500 standard m³/per m³ of the first feed 110. The gas richin hydrogen can be from one or more sources within the refinery, such asa recycled gas, a make-up gas, or other sources.

Generally, the bubble column reactor 200, which is depicted in partialcross-section about the middle of the reactor 200, has a first inlet230, a second inlet 240, a first outlet 250, and a second outlet 260.The first feed 110 can be provided to the first inlet 230, so that asuspension of the petroleum fraction and the catalyst particles may fillmuch of the bubble column reactor 200. Generally, the suspension of thepetroleum fraction and catalyst particles flows downward in the bubblereactor 200 towards the first outlet 250. The second feed 130 can beprovided to the second inlet 240 and the reactant gas can rise in thebubble column reactor 200 towards the second outlet 260. Typically, thebubble column reactor 200 is operated under any suitable conditions,such as a pressure of about 3.5-about 27.6 MPa, preferably about6.9-about 20.7 MPa, and optimally about 10.3-about 17.2 MPa; a reactortemperature of about 350-about 600° C., preferably about 400-about 500°C., and optimally about 430-about 460° C.; and at a liquid hourly spacevelocity (LHSV) of about 0.1 hr⁻¹-about 2.0 hr⁻¹, preferably about 0.2-about 1.0 hr⁻¹, and optimally about 0.25-about 0.75 hr⁻¹.

The second feed 130 can be provided at the second inlet 240 incommunication with a gas distributor 270. The gas distributor 270 can beany suitable shape, such as a linear, elongated tube, a grid in the formof a prism, or a ring, with a plurality of orifices providing adistribution of hydrogen in the bubble reactor 200. The hydrogen canbubble upwards through the reactor 200 so that the solid-in-liquidsuspension and the gas particles are in a counter-current flow 140. Thesolid-in-liquid suspension can flow downward towards a base 210 of thebubble column reactor 200 to the first outlet 250 and provide a firstproduct 134, which is typically a suspension of solid catalyst particlesin at least a partially converted liquid petroleum fraction. Generally,one or more unreacted gases, such as hydrogen, and one or more productgases, such as one or more naphtha distillate components, escape upwardsto a top 220 of the bubble column reactor 200 and can exit the secondoutlet 260 to provide a second product 138.

In one preferred embodiment, a level control system 280 can be provided.The level control system 280 can include a level controller 282 and acontrol valve 284. A level control system 280 can allow disengagement ofthe solid-in-liquid suspension and the product gas at the top 220 of thebubble column reactor 200. Thus, a gap 225 is created between theproduct gases and the solid-in-liquid suspension. As a consequence,additional equipment, such as a hot separator, can be avoided and suchan elimination can provide cost savings. Although the control valve 284is depicted on the first feed stream 110, it should be understood thatthe one or more control valves can be located at other locations, suchas proximate to the first outlet 250, instead of the control valve 284.

In operation, the first feed 110 can be received in the first inlet 230to substantially fill the bubble column reactor 200, while the secondfeed 130 including the gas rich in hydrogen can be received in thesecond inlet 240. The solid-in-liquid suspension can flow downward incounter-flow to the rising gas. The solid-in-liquid suspension can beconverted with the partial pressure being greatest near the first outlet250. The at least partially converted solid-in-liquid suspension canexit through the first outlet 250, as a solid-in-liquid suspension“slurry” product 134. The level control system 280 can create the gap225 to allow a gas of one or more unreacted gases, e.g., hydrogen, andone or more product gases, such as naphtha distillate components, exitas the second product 138 via the second outlet 260.

Generally, the bubble column reactor 200 is operated with acounter-current flow 140 to increase the hydrogen partial pressureproximate to the base 210 and the first outlet 250 to facilitateconversion, saturation, hydrodesulfurization, and/orhydrodenitrification, such as hydrogenating one or more unsaturatedaromatic and non-aromatic compounds, and removing at least one ofnitrogen and sulfur from one or more hetero-compounds. In addition, thecounter-current flow design can prevent solids accumulation at the base210, providing time and/or capital savings by eliminating or reducingoperators' vigilance and/or equipment.

Referring to FIG. 2, a second system 300 is depicted. The second system300 can include a plurality of bubble column reactors 350, namely afirst bubble column reactor 400 and a second bubble column reactor 500.The bubble reactors 400 and 500 and their respective components aregenerally the same and can generally receive the same feeds and operatein the same manner as the bubble column reactor 200 described in thefirst system 100. However, the second bubble column reactor 500 canoperate up to about 50° C., preferably up to about 25° C., and optimallyabout 5-about 15° C. higher than the first bubble column reactor 400.Moreover, a liquid hourly space velocity (LHSV) for the second system300 as a whole can be about 0.1 hr⁻¹-about 2.0 hr⁻¹, preferably about0.2-about 1.0 hr⁻¹, and optimally about 0.25-about 0.75 hr⁻¹.

The first bubble column reactor 400 can include a base 410, a top 420, afirst inlet 430, a second inlet 440, a first outlet 450, a second outlet460, and a gas distributor 470. The first bubble column reactor 400 canreceive a first feed 310, typically a solid catalyst in a liquidpetroleum fraction suspension at the first inlet 430, and a second feed314 including a gas rich in or substantially including hydrogen at thesecond inlet 440. Generally, a stream including catalyst can be combinedwith a stream including a petroleum fraction before forming the firstfeed 310, as described above for FIG. 1. The first bubble column reactor400 can produce a base product 318, which can be at least a partiallyconverted petroleum fraction suspending catalyst particles, and a secondproduct 322 including a gas. The gas can include one or more unreactedgases and naphtha distillate components.

A level control system 480, including a level controller 482 and acontrol valve 484, can provide a gap 425 of one or more gases and thesolid-in-liquid suspension in the first bubble column reactor 400 todisengage the one or more gases, similarly as described above for thelevel control system 280 for the system 100.

The bubble column reactor 500 can include a base 510, a top 520, a firstinlet 530, a second inlet 540, a first outlet 550, a second gas outlet560, and a gas distributor 570. The second bubble column reactor 500 canreceive a third feed 326, typically a solid-in-liquid suspension of thebottom product 318 of the first bubble column reactor 400, at the firstinlet 530. However, it should be understood that the first feed 310,typically a solid-in-liquid petroleum fraction suspension, to the firstbubble column reactor 400 is generally different, e.g., heavier, thanthe third feed 326 to the second bubble column reactor 500 due toconversion of various fractions in the first feed 310. Moreover, anoptional stream 324 that can include a heavy gas oil stream rich inpolar aromatics, such as a slurry hydrocracker vacuum gas oil or a fluidcatalytic cracking slurry oil, can be combined with the bottom product318 by, e.g., opening a valve 328. The combined stream 326 can haveabout 5-about 50%, by weight, of the stream 324 based on the weight ofthe combined stream 326. Adding the stream 324 can control cokingreactions in the bubble column reactor 500.

A fourth feed 330 including a gas rich in or substantially includinghydrogen may be provided at the second inlet 540. The gas provided asthe fourth feed 330 can be from the same or a different source as thesecond feed 314. In one preferred embodiment, the second feed 314 can bea recycle gas and the fourth feed 330 can be a make-up gas. The secondbubble column reactor 500 can produce a third product 334, which can bea solid-in-liquid suspension of a catalyst and another at leastpartially converted petroleum fraction. A fourth product 338 can includea gas of one or more unreacted gases, e.g., hydrogen, and one or moreproduct gases, such as naphtha distillate components.

A level control system 580, including a level controller 582 and acontrol valve 584, can separate gases and the liquid suspension in thebubble column reactor 500 and can provide a gap 525, similarly asdescribed above for the level control systems 280 and 480.

In operation, the first feed 310 can fill a substantial portion of thebubble column reactor 400 and flow downward toward the first outlet 450.The second feed 314 entering near the base 410 through the second inlet440 is provided to the gas distributor 470. The gas can bubble upwardscounter-currently through the solid-in-liquid suspension. The gas canflow upwards towards the second outlet 460. Any one or more unreactedgases and gas products can be comprised in the second product 322. Thereacted and unreacted portions of the solid-in-liquid suspension canflow downwards out the first outlet 450 to provide a feed to the secondbubble column reactor 500.

The bottom product 318 from the first bubble column reactor 400 canenter the first inlet 530 as a third feed 326. The feed 326 can enterthe reactor and fill a substantial portion of the reactor 500. At thesecond inlet 540, a second feed of a gas rich in hydrogen can beprovided. The gas can enter the inlet 540 to the gas distributor 570 andbe distributed through the solid-in-liquid suspension. Generally, thesolid-in-liquid suspension and the gas can be in counter-current flow.The reacted and unreacted portions of the solid-in-liquid suspension canflow downwards out the first outlet 550 to provide the third product334, which can be a suspension of one or more at least partiallyconverted petroleum fractions and catalyst particles. Any unreactedgases and gas reaction products can be comprised in the fourth product338. The second product 322 may be combined with the fourth product 338and can exit the second system 300.

Optionally, the solid-in-liquid suspension “slurry” product 334 can besent to a warm high pressure separator. An exemplary warm high pressureseparator can operate at a temperature of about 40-about 200° C. and apressure of about 100 kPa-20,000 kPa. The combined gas products 322 and338 can be sent to a cold high pressure separator. An exemplary coldhigh pressure separator can operate at a temperature of about 32-about100° C. and at a pressure of about 100 kPa-about 20,000 kPa. Although awarm high pressure separator and a cold high pressure separator havebeen disclosed, any equipment or process can be further used to processthe product streams. Any such separators can be provided to separate alighter fraction from a heavier one. Similarly, the equipment, such asseparators, and/or processes can also be used with the system 100described above.

One benefit of the second system 300 can be improved energy efficiencybecause the solid-in-liquid suspension product 318 of the first bubblecolumn reactor 400 may not be reheated for a subsequent reactor, such asthe second bubble column reactor 500.

Without further elaboration, it is believed that one skilled in the artcan, using the preceding description, utilize the present invention toits fullest extent. The preceding preferred specific embodiments are,therefore, to be construed as merely illustrative, and not limitative ofthe remainder of the disclosure in any way whatsoever.

In the foregoing, all temperatures are set forth uncorrected in degreesCelsius and, all parts and percentages are by weight, unless otherwiseindicated.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention and, withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

1. A system for reacting a first feed comprising a petroleum fractionstream having at least about 90%, by volume, with a boiling point of atleast about 300° C., comprising: A) a bubble column reactor; wherein thebubble column reactor comprises: 1) a first inlet for the first feed;and 2) a second inlet for a second feed comprising a gas rich inhydrogen; wherein the petroleum fraction is in counter-current flow withrespect to the gas rich in hydrogen inside the bubble column reactor. 2.The system according to claim 1, wherein the bubble column reactorfurther comprises a gas distributor proximate to a base of the bubblecolumn reactor.
 3. The system according to claim 2, wherein the firstinlet for the first feed is proximate to a top of the bubble columnreactor.
 4. The system according to claim 1, further comprising a levelcontrol system to permit disengagement of a second product, comprising agas, from a petroleum fraction at a top of the bubble column reactor. 5.The system according to claim 1, wherein the bubble column reactorcontains a catalyst comprising at least one group VIII metal with adiameter of less than about 45 microns entrained in a petroleumfraction.
 6. The system according to claim 5, wherein the at least onegroup VIII metal comprises iron.
 7. The system according to claim 1,wherein the first feed comprises at least one of an atmospheric towerbottom and a vacuum tower bottom.
 8. The system according to claim 3,wherein a partial pressure of hydrogen is greater proximate to a firstoutlet for a first product comprising a petroleum fraction than thefirst inlet for the first feed.
 9. A system for reacting a first feed ina plurality of bubble column reactors, comprising: A) a first bubblecolumn reactor receiving first and second feeds, wherein the first feedcomprises a petroleum fraction stream having at least about 90%, byvolume, with a boiling point of at least about 300° C., and the secondfeed comprises a first gas rich in hydrogen wherein the petroleumfraction is in counter-current flow with respect to the first gas richin hydrogen in the first bubble column reactor; and B) a second bubblecolumn reactor receiving a third feed of a bottom product from the firstbubble column reactor comprising another petroleum fraction, and afourth feed comprises a second gas rich in hydrogen wherein the anotherpetroleum fraction is in counter-current flow with respect to the secondgas rich in hydrogen in the second bubble column reactor.
 10. The systemaccording to claim 9, wherein the first and second gases rich inhydrogen are from a same source.
 11. The system according to claim 9,wherein the first and second gases rich in hydrogen are from differentsources.
 12. The system according to claim 9, wherein each of the firstbubble column reactor and the second bubble column reactor comprises agas distributor proximate to a base of the respective bubble columnreactor.
 13. The system according to claim 9, further comprisingrespective level control systems for the first and second bubble columnreactors.
 14. The system according to claim 9, wherein each of the firstand second bubble column reactors contains a catalyst comprising atleast one group VIII metal with a diameter of less than about 45 micronsentrained in a respective petroleum fraction.
 15. The system accordingto claim 14, wherein the at least one group VIII metal comprises iron.16. The system according to claim 9, wherein the first feed comprises atleast one of an atmospheric tower bottom and a vacuum tower bottom. 17.The system according to claim 9, wherein the first feed comprises acatalyst comprising at least one group VIII metal with a diameter ofless than about 45 microns.
 18. A process for reacting a first feedcomprising a petroleum fraction stream having at least about 90%, byvolume, with a boiling point of at least about 300° C., comprising: I)passing counter-currently a petroleum fraction entraining a catalystwith respect to a gas rich in a hydrogen gas in a bubble column reactor.19. The process according to claim 18, wherein the catalyst comprisesiron and has a diameter of less than about 45 microns.
 20. The processaccording to claim 18, wherein the process hydrogenates one or moreunsaturated aromatic and non-aromatic compounds, and removes at leastone of nitrogen and sulfur from one or more hetero-compounds.